Decal or transfer layer adhered to a carrier layer without adhesive

ABSTRACT

TRANSFERS COMPRISING INDICIA SUPPORTED ON A CARRIER SHEET ARE PREPARED FROM NON-POROUS COMPONENTS WHICH ARE ADHERED TOGETHER WITHOUT THE USE OF ANY ADHESIVE. THE LAYERS ARE HELD TOGETHER BY MEANS OF DIFFERENCE BETWEEN THE EXTERNAL OR AMBIENT IR PRESSURE AND THE PRESSURE OF AIR BETWEEN THE LAYERS. THE TRANSFER LAYER IS THUS ADAPTED TO BE READILY REMOVABLE FROM THE CARRIER LAYER BY PERFORMING OR OTHERWISE, RUPTURING ONE OF THE LAYERS TO ADMIT AIR BETWEEN THE LAYERS.

United States Patent 3,562,087 DECAL 0R TRANSFER LAYER ADHERED TO ACARRIER LAYER WITHOUT ADHESIVE John Percy Wigzell, Bulawayo, Rhodesia,assignor to Vactran Patents (Private) Limited, Bulawayo, Rhodesia, acorporation of Rhodesia No Drawing. Filed Dec. 7, 1965, Ser. No. 512,215Claims priority, application/Rhodesia, Dec. 17, 1964, 469 6 Int. Cl.B321) 3/00 U.S. Cl. 161-127 7 Claims ABSTRACT OF THE DISCLOSURE Thisinvention relates to transfers of the general type in which indicia aresupported on a carrier sheet and are capable of being released therefromto adhere to a receiving surface.

It is, of course, well-known to attach indicia to a carrier sheet bymeans of an adhesive and to secure their release by dissolving theadhesive in a liquid medium.

So called dry transfer materials are also known and they may require theapplication of heat or other means to separate the two elements.

The characteristic feature of known transfers is, however, the provisionof an adhesive bond between the indicia and the carrier sheet which isbrought into being either through the use of an independent adhesivelayer or by using materials which naturally stick to one another.

The object of the present invention is to provide a transfer employingas indicia and carrier sheet respectively, materials which are not orare only lightly self-adherent one to the other and causing them toadhere firmly together by creating a pressure differential between theouter exposed faces of the two elements and the zone of contact betweenthem.

In accordance with one aspect of the invention, there is provided amethod of making a transfer comprising the step of applying an indiciato a carrier sheet so that a gastight rupturable zone of sub-atmosphericpressure is disposed between the abutting faces of the indicia and thecarrier. In other words, the periphery of an area of the indicia sheetor layer is in direct contact with the carrier sheet so as to define aspace which is gas tight, rupturable and also is at subatmosphericpressure.

The indicia and the carrier are thus retained in firm contact with oneanother by reason of the fact that the exposed outer faces of the twoelements are subjected to atmospheric pressure, whereas the abutingfaces are subjected to sub-atmospheric pressure, or a complete vacuum iscreated in the gas-tight zone.

To release the indicia from the carrier sheet, it is only necessary torupture the enclosed space formed by the carrier and indicia layers,i.e., the gas-tight zone, as by puncturing the carrier sheet, whereuponthe two pressures become equalised and little or no separating force isrequired.

The exposed face of the indicia will normally be coated with anadhesive, e.g. a contact adhesive of the non-drying type, by means ofwhich it is caused to adhere to a receiving surface. Such adhesive willbe covered in known manner with a protective layer which is stripped offimmediately before the indicia is brought into contact with the surfaceto which it is to be applied.

To facilitate accurate location and registration of the indicia, it ispreferred to use a carrier sheet which is transparent, or at leasttranslucent. It has been found that a polyalkylene derivative, such aspolyethylene or poly propylene, in flexible sheet form is a convenientmaterial to use for this purpose. A sheet of at least 300 gauge issuitable.

The sub-atmospheric gas-tight zone may be obtained in one of severalways. In the case of solid indicia applied to the carrier sheet, air maybe expelled from the relevant zone by forcing the indicia and carriersheet together. For example, a pressure applying roller may be used orthe required result may be derived by a stamping operation. Inaccordance with this method for obtaining the sub-atmospheric pressurezone the carrier sheet and/or the indicia must be sufiiciently resilientto enable opposed surfaces of the carrier sheet and indicia to close onone another, so expelling air, and subsequently to move apart underresilient deformation.

As an alternative to the solid mounted indicia the indicia may beapplied to the carrier as liquids or pastes which exclude air as theyare applied. When the wet state indicia set they adhere to the carrierthrough zones of reduced pressure which have been formed betweenthemselves and the carrier. The fluids may be applied by roller, brush,or by means of a spray; with or without a stencil. Also a particularlyeffective method of applying the wet state indicia is by a silk screenprinting process.

Oil and lacquer based paints and inks having sufficient flexibiilty whendry to withstand bending have been found to be satisfactory materials toapply to the flexible carrier sheet and they provide indicia which aredurable and of a pleasing appearance. Enamel paint is particularlysuitable. It is preferred that the thickness of these indicia should beabout 0.0025".

Collodium geltine, egg white or pitch bitumen may also be used to formindicia.

Carrier sheets having a high gloss surface should be used with highgloss indicia; conversely, matt or semi-matt sheets should be used withindicia having a matt finish.

A preferred method for the formation of transfers according to theinvention comprises the production of the desired indicia, for examplelettering, in the usual manner with the aid of a Starlettograph machineon clear film. The images are transferred to a piece of Hi Fi GreenPhotographic stencil material which is then exposed to a quartz lamp ina vacuum frame. The stencil is then developed in A and B developer andstripped in the usual manner.

The stencil is then brought to a stainless steel mesh screen stretchedon an aluminum frame. All open areas of the screen are blocked out toleave only the stencil area.

A millboard base board, first coated with lacquer-based silk screen inkon both sides to prvent absorbtion, is coated on one side with syntheticbees wax to retain a carrier sheet. The carrier sheet is cut from 500gauge, heat drawn low density polyethylene, and is rolled onto the baseboard by means of a mangle type roller. This operation gives a degree ofstretch to the polyethylene carrier sheet and ensures that it is evenlyadhered to the base board.

Printing of the indicia is then commenced by lowering the screen intoposition over a base board with carrier sheet afiixed. The base boardmay conveniently be retained in position by a vacuum table. Enamel inkis then poured onto the upper surface of the screen and the ink ispressed through the stencil onto the carrier by means of a squeegee. Thesnap distance, which should be between one eighth and one quarter of aninch but which may be more or less depending on the particularcircumstances, partly regulates the degree of reduced pressure that willbe formed between the indicia material and the carrier sheet material.The pressure that is applied by the squeegee, through the screen to thecarrier, accounts for the remainder of the reduced pressure effect.

When the carrier has been printed, it is racked in a dust free place forabout 6 hours at about 75 Fahrenheit until properly dry. Once it is dry,it is overprinted with a contact adhesive through the same screen. Oncethis adhesive has settled, a silicone treated backing sheet is placedover the carrier and the carrier sheet is stripped from the base board.The base board may then be re-used for further operations.

It will be understood that the carrier sheet and the indicia must benon-porous to permit the formation of the gas-tight zone between themand, further, that the carrier sheet must not be soluble in, orotherwise deleteriously aifected by, the substance used for theindiciae.

If the indicia has been prefabricated in solid form, it may be appliedto the carrier sheet by pressure which expels the air between theadjacent faces.

It will be appreciated that the adhesive used for securing the indiciato the surface upon which it is to be received may be of any desiredstrength. Thus, it is not necesary to use an exeptionally strongadhesive to overcome the adhesive force between the indicia and thecarrier sheet as is required in certain known types of dry transfers.

I claim:

1. A transfer sheet comprising an indicia layer and a carrier layertherefor;

both of said layers being adapted to substantially exclude air fromentry between said layers;

both of said layers being in direct contact about the periphery of anarea of said layers;

the said layers Within the said periphery being separated to form anenclosure which is gas tight, rupturable, and at subatmosphericpressure;

said indicia layer being adhered to said carrier layer substantially bymeans comprising said subatmospheric pressure and thereby, said indicialayer also being adapted to being removed from said carrier layer byrupture of said enclosure. 2. The sheet of claim 1 in which the exposedface of the indicia is coated -with an adhesive.

3. The sheet of claim 1 in which the carrier sheet is flexible.

4. The sheet of claim 1 in which the carrier sheet is transparent.

5. The sheet of claim 1 in which the carrier sheet is translucent.

6. The sheet of claim 1 in which the carrier sheet comprises apolyalkylene derivative.

7. The sheet of claim 1 in which the carrier sheet is polyethylene of atleast 300' gauge.

References Cited UNITED STATES PATENTS 2,586,039 2/1952 Heggedal 40-1253,013,917 12/1961 Karlan et al. 161-406 3,065,120 11/1962 Avelar 161-4063,294,611 12/1966 Vomela 161-406 1,706,038 3/1928 Owens 101-128.42,156,680 5/1939 Dennison 156104X 2,397,827 4/1946 Williams 1562302,408,147 9/1946 Kneale 156230 2,558,803 7/1951 Wittgren 156--2402,591,779 4/1952 Buck 156230X 2,910,723 11/1959 Traver 204168 3,014,82812/1961 Reese 156247X 3,212,913 10/1965 Mackenzie 156-230 FOREIGNPATENTS 589,276 12/1959 Canada 156--23O 393,132 6/1933 Great Britain,1,293,384 4/1962 France 156-230 JOHN T. GOOLKASIAN, Primary Examiner W.E. HOAG, Assistant Examiner US. Cl. X.R.

ll7-3.l, 7; l56--230, 347, 253; l6140, 116, 146, 406.

